Hot water storage tanks are used to provide and circulate hot water throughout a plumbing system. Hot water storage tanks may include a port at a designated height on the tank to allow for excess water to exit the tank. It is desirable to allow water to exit the tank to prevent excess water from accumulating in the tank, as the excess water can overflow out the top of the tank, may lose temperature quickly, and may cause corrosion problems, as the water may leak and/or cause the tank to rust.
Valves currently used for water level overflow control typically employ a large float arm that is attached to a valve. When the water level rises, the float rises, causing the arm to rotate. This rotation causes the valve to open and allows water to escape the tank. These float arm devices are large and require a large height change in water for the ball to rise enough to in turn fully open or close the valve. This may lead to the valve being left open for longer than desired and may cause excessive water to be lost, including water vapor loss. As water vapor is at a higher temperature than its corresponding liquid (it is in the vapor state, which is a higher energy than a liquid state), excess loss of water vapor and energy results in heat loss from the tank that decreases the overall efficiency of the hot water storage device.
Furthermore, many of the float arm systems employed in the prior art use electromagnetic valves or valves with sealing faces. In the case of a non-pressurized tank, a fully sealed valve may not be desirable when there are no other means of exposure to the outside atmosphere.
Various valve mechanisms are known and have been employed in various tanks. U.S. Pat. No. 4,640,307 (“the '307 patent”) to Roberts discloses a float valve mechanism for a hot water tank. The '307 patent provides a valve member cover that is connected to a lever. However, the lever has a groove, which is always open, such that water vapor from the tank will exit the tank and cause the overall efficiency of the tank to not be maximized. Furthermore, the '307 patent suffers from being large and requiring a large height change in the water.
In another example of a drainage system, U.S. Pat. No. 3,709,202 to Brown (“the '202 patent”) discloses a crankcase draining recycling system having a valve operable by a float in the drainage tank. U.S. Pat. No. 2,292,509 to Carson (“the '509 patent”) discloses an automatic valve for liquid containers having a disc valve connected to a flange and bifurcated lever. U.S. Pat. No. 2,211,296 to Shaft (“the '296 patent”) disclosed an automatic ball float tank seal that forms a seal once the water level reaches the desired level. U.S. Pat. No. 922,142 to Hogg (“the '142 patent”) discloses an automatic pipeline suction valve having a float that keeps the valve open so long as the float maintaining depth is maintained.
Other designs that have been used for water level overflow control employ an electromagnetic valve, which adds cost and complexity to the system. Electromagnetic valves require an electrical supply to operate correctly, resulting in additional energy consumption and decreasing the overall efficiency of the hot water storage system.
In the aforementioned prior art patents, the problem of preventing excessive water from being lost, including water vapor loss, is not solved. Moreover, the prior art does not solve the problem of designing a valve that quickly, accurately and reliably opens to allow water to exit the drain port once water reaches a certain level, which is small, simple and has a low cost.
It is therefore desired to provide an overflow valve that overcomes the drawbacks of the prior art by quickly, accurately and reliably opening the overflow valve to allow water to exit the drain port once the water reaches a certain level.
It is further desired to minimize water vapor loss while the valve is in the closed position and to minimize high energy water vapor loss in general.
It is further desired for a valve to allow for external air intake should negative pressure in the tank occur, so that the pressure in the tank can be stabilized.
It is yet further desired to minimize heat loss from the tank through the valve and valve assembly.